Design and Construction of an Automatic Voltage Regulator for a Synchronous Alternator

The Automatic Voltage Regulator (AVR) is necessary to keep the terminal voltage of a loaded alternator constant. It is widely used to increase the regulation and stability of synchronous alternators especially in bulk power plants where efficiency and stability is of paramount importance. The AVR is a feedback controller that varies the excitation of the alternator to support a constant output voltage by increasing or decreasing the excitation level of the alternator as the load varies. In this research, the transfer functions of the various stages of the AVR are decided for the purpose of the design of the Voltage Regulator. The performance of the AVR is decided by the basic no load and load test on the alternator. The results show that there was tremendous improvement in the terminal voltage of the alternator with the AVR and a significant drop in the terminal voltage of the alternator without the AVR.